The FBI interviewed over 700 witnesses of the incident and 270 of them claimed to have seen a ball of light (similar to a missile) streak from the surface up into the sky, followed by the massive explosion of the aircraft.
Two Air National Guard helicopter pilots were on a training mission, over the ocean, heading back to their base on Long Island. A few thousand feet below Flight 800, heading directly toward it, they saw a red-orange flare-like object heading skyward. Then there was a small explosion, followed immediately by a large explosion.
A U.S. Navy electronic technician was traveling on a US Air Jet, gazing out the window, when he spotted a "flare" rising from below. Soon, there was a small midair explosion, followed by a much bigger explosion.
Hundreds of witnesses have given similar accounts of an object streaking skyward just prior to the explosion.
The timing of this incident on July 17, a special holiday in the Muslim world, is important.
Coincidentally, there was an El Al 747 (Israeli airlines) flight scheduled to take off out of Kennedy at about the same time as TWA Flight 800 but it was running late. It would be an obvious prime target for Muslim terrorists.
In June of 1996, members of several terrorist groups held a meeting in Tehran, Iran. Soon thereafter, three weeks before TWA Flight 800 was downed, the U.S. Air Force barracks (Khobar Towers) in Saudi Arabia were attacked by a truck bomb, killing 19 and wounding 372 military personnel. President Clinton immediately placed the military on the highest alert since the Cuban Missile Crisis.
http://www.areawidenews.com/blogs/1215/entry/19541/